Write-Up: No Start + 3 min delay / Disabling PASS-Key II Security

I recommend reading page 12 of this thread, where I shared all I know on this issue.

AA wrote:

I recommend reading page 12 of this thread, where I shared all I know on this issue.

I initially cut the white/black wire but this resulted in no start at all. no 3 min wait when disconnected, but no start. reconnected and 3 min wait returns or if i'm lucky POS will start.

All right, maybe it's safe to assume your ignition cylinder or key aren't supplying the correct resistance. I had a "plan B" in case cutting the wire didn't work. I purchased a trimmer resistor from Radio Shack. This could be adjusted to mimic the resistance of the key pellet. Wiring it across the blk/wht and purp/blk wires should convince the security module that a correct key is inserted.

Here is a trimmer like the one I bought, shown larger than actual size. 1k ohms should be enough. 5k would also work:

GreenJeanS wrote:

ok i have been looking long and hard on this vats/passkey issue for my 1997 Riviera. I have been living with the problem for longer than i can remember and i have decided enough is enough. I have got to do something and get rid of this thing. I was going to go the route of the resistor in the harnesses but have decided maybe there is another way to overcome these problems. what i am wanting to do it ground the park/neutral switch in effect stopping the decoder module from keeping the the starter enable relay from working. Please someone who knows about this help guide me in the right direction.

In a word, No, because you can't manage the control strategy within the powertrain control or the pass-key modules.

AA wrote:

All right, maybe it's safe to assume your ignition cylinder or key aren't supplying the correct resistance. I had a "plan B" in case cutting the wire didn't work. I purchased a trimmer resistor from Radio Shack. This could be adjusted to mimic the resistance of the key pellet. Wiring it across the blk/wht and purp/blk wires should convince the security module that a correct key is inserted.

Here is a trimmer like the one I bought, shown larger than actual size. 1k ohms should be enough. 5k would also work:

I have purchased the resistors that match my key. I will try and wire it into the passkey decoder and get back to you.

albertj wrote:

GreenJeanS wrote:

ok i have been looking long and hard on this vats/passkey issue for my 1997 Riviera. I have been living with the problem for longer than i can remember and i have decided enough is enough. I have got to do something and get rid of this thing. I was going to go the route of the resistor in the harnesses but have decided maybe there is another way to overcome these problems. what i am wanting to do it ground the park/neutral switch in effect stopping the decoder module from keeping the the starter enable relay from working. Please someone who knows about this help guide me in the right direction.

In a word, No, because you can't manage the control strategy within the powertrain control or the pass-key modules.

I'm sorry, i do not follow? it would seem that if both the park/neutral safety switch and the fuel pump relay are directly grounded vats would be unable to stop the car from starting?

I don't know exactly how the Pass-Key and PCM interact to prevent the car from starting -- and even if I did, that would be proprietary to GM, they are diligent about protecting their IP, and I respect that diligence.

Given that you have tried to get around them and your work around has not worked, the control strategy that they implemented in those boxes (the PCM and Pass-Key) appears to have succeeded.

You might want to try reversing your wiring modifications and getting replacement pass-key module from a junkyard. That failing -- there is more than enough info in this thread, including source for a device you can install, and instructions for a simple resistor work-around that's no secret.

Peace out.

Albertj

albertj wrote:

I don't know exactly how the Pass-Key and PCM interact to prevent the car from starting -- and even if I did, that would be proprietary to GM, they are diligent about protecting their IP, and I respect that diligence.

Given that you have tried to get around them and your work around has not worked, the control strategy that they implemented in those boxes (the PCM and Pass-Key) appears to have succeeded.

You might want to try reversing your wiring modifications and getting replacement pass-key module from a junkyard. That failing -- there is more than enough info in this thread, including source for a device you can install, and instructions for a simple resistor work-around that's no secret.

Peace out.

Albertj

you contradict yourself here i am afraid. You speak of wireing modifications that i have done that have not worked

Quote :

Given that you have tried to get around them and your work around has not worked, the control strategy that they implemented in those boxes (the PCM and Pass-Key) appears to have succeeded.

and then suggest i do the same modification

Quote :

here is more than enough info in this thread, including source for a device you can install, and instructions for a simple resistor work-around that's no secret.

this "device" ,for $180 if that is the one you speak of, no longer offers build it yourself instructions and have seen next to no reviews of the "module" working in the riviera. [i]

GreenJeanS wrote:

AA wrote:

I recommend reading page 12 of this thread, where I shared all I know on this issue.

I initially cut the white/black wire but this resulted in no start at all. no 3 min wait when disconnected, but no start. reconnected and 3 min wait returns or if i'm lucky POS will start.

Above, you said you initially cut the white/black wire. That's a modification. In the later posts there is no information showing that you reversed the modification.

So...

if you have not already, you might want to go restore your wiring. With that done, odds are you can get a working PassKey module from an auto recycler for short money. As for the $180 device, that's a good point, and if you read the earlier posts you'd conclude I'm not a fan of it.

An aside: I think it'd be interesting to find the root cause of why pass-key systems quit. As far as I know not that many of them fail. Maybe there is a systematic problem, like a failure within the ignition switch or using the car to jump-start other cars (the Riv has unusual instructions for jumpstarting) or some such. Kinda wonder.

Albertj

albertj wrote:

GreenJeanS wrote:

AA wrote:

I recommend reading page 12 of this thread, where I shared all I know on this issue.

I initially cut the white/black wire but this resulted in no start at all. no 3 min wait when disconnected, but no start. reconnected and 3 min wait returns or if i'm lucky POS will start.

Above, you said you initially cut the white/black wire. That's a modification. In the later posts there is no information showing that you reversed the modification.

So...

if you have not already, you might want to go restore your wiring. With that done, odds are you can get a working PassKey module from an auto recycler for short money. As for the $180 device, that's a good point, and if you read the earlier posts you'd conclude I'm not a fan of it.

if you notice in my quote above i said i reconnected the wire and my 3 min wait returned. i am sorry for the confusion. without the wire connected the car never attempted to start. reconnecting it was the only option.

Quote :

An aside: I think it'd be interesting to find the root cause of why pass-key systems quit. As far as I know not that many of them fail. Maybe there is a systematic problem, like a failure within the ignition switch or using the car to jump-start other cars (the Riv has unusual instructions for jumpstarting) or some such. Kinda wonder.

Albertj

I have considered purchasing the passkey decoder module from a recycler, but i am afraid finding the correct key value might be easier said than done. is there a way that i can determine that it is that module and not the pcm that is malfunctioning? i don't really have $$ to buy something that is not the problem. Thank you for your continued replies, this issue has been with me for well over 3 yrs.

Yeah, and sorry about my misunderstanding and skimming instead of reading.

There are sites on ebay that will sell you a pcm for short money, I bought from one in the past but can't find papers. Or I'd give you their info. They should be easy to find there or using google shopping... they are not hiding.

As for the passkey module make some junkyard phone callus, just ask if they have a module for your year car. All you need then is the VIN off the car it came from and then any GM dealer can look up what the key/pellet resistor value is on that one. I think at one time you could find that data on line but I honestly forget how, it's been a longtime. I'd. Try a google search.

I still kinds wonder if the problem is actually the ignition lock or switch.

A dealer has Tech Ii and other tools that make trouble finding easier but you already mentioned issues with the dealers you have visited so far. Can't. Help you with that one. I would also inspect steering column wiring for chafing or damaged connectors, or breaks at the terminal crimps.

albertj wrote:

I think at one time you could find that data on line but I honestly forget how, it's been a longtime. I'd. Try a google search.

This?

Value K-Ohms
1 0.402 (acceptable range .386-.438)
2 0.523 (acceptable range .502-.564)
3 0.681 (acceptable range .650-.728)
4 0.887(acceptable range .850-.942)
5 1.130 (acceptable range 1.085-1.195)
6 1.470(acceptable range 1.411-1.549)
7 1.870(acceptable range 1.795-1.965)
8 2.370(acceptable range 2.275-2.485)
9 3.010 (acceptable range 2.890-3.150)
10 3.740(acceptable range 3.590-3.910)
11 4.750(acceptable range 4.560-4.960)
12 6.040(acceptable range 5.798-6.302)
13 7.500(acceptable range 7.200-7.820)
14 9.530(acceptable range 9.149-9.931)
15 11.801 (acceptable range 11.320-12.290)

Yes, thank you.

Remember you can tap in to the lock cylinder wiring in the right kick panel. No need to go through the steering column. I like the trimmer idea because fixed resistors have a tolerance, and never know if the security module will like your resistor, even though it's supposed to be within spec. At very least use a precision resistor with tighter +/- tolerance.

AA wrote:

Remember you can tap in to the lock cylinder wiring in the right kick panel. No need to go through the steering column. I like the trimmer idea because fixed resistors have a tolerance, and never know if the security module will like your resistor, even though it's supposed to be within spec. At very least use a precision resistor with tighter +/- tolerance.

Trimpots are always a good idea.

AA wrote:

All right, maybe it's safe to assume your ignition cylinder or key aren't supplying the correct resistance. I had a "plan B" in case cutting the wire didn't work. I purchased a trimmer resistor from Radio Shack. This could be adjusted to mimic the resistance of the key pellet. Wiring it across the blk/wht and purp/blk wires should convince the security module that a correct key is inserted.]

albertj wrote:

I still kinds wonder if the problem is actually the ignition lock or switch.

AA wrote:

Remember you can tap in to the lock cylinder wiring in the right kick panel. No need to go through the steering column. I like the trimmer idea because fixed resistors have a tolerance, and never know if the security module will like your resistor, even though it's supposed to be within spec. At very least use a precision resistor with tighter +/- tolerance.

looks like the ignition contacts must be failing or the wire somewhere in between. I placed a 1/2 watt 1.5k-ohm 5% tolerance resistor (per my key pellet) in between the white/black and purple/black wires going into the passkey decoder module and have not had a no start yet. This was only done this afternoon so further testing will be needed to endure it is working and not a fluke. I also would like to find somewhere to copy the key minus the pellet to verify that the contacts were the problem. Thank you to all who posted to help me. I will get back once i have verified that the problem no longer persists.

For mine, I wrapped a thin piece of transparent tape around the pellet and inserted the key to test. It should start with your resistor installed.

AA wrote:

For mine, I wrapped a thin piece of transparent tape around the pellet and inserted the key to test. It should start with your resistor installed.

tape test done. resistor wired into passkey decoder is working. F#$K YEAH!!!! now to get it soldered up and wrap it!

OK, I admit that this doesn't really apply to this thread, but Aaron, I couldn't find a "just plain" Security System Problem thread with the Search function.........

ANYway, I just had something happen that I cannot find in the '98 FSM that I have in my computer (my car being a '97...)

In that GM SPO eManual, I have tracked down every thread and I can't find any example where the Security light stays on at ALL times - And by this I don't mean the usual "all" times, I mean Start, Run, Off, Open the damned doors and play with the keyfob kind of ON!!

While I actually got myself home, I can't find an electronic reason why I did. While I was trapped outside Safeway in the rain, the only thing that seemed possible to go after was the starter-relay, which is above the left footwell with the BCM & LCM, while the (solid-state) module is over the passenger side footwell...

I 'popped' the E-Brake once and literally pounded on the left-side trim piece with my foot,
and that stubborn Security lite went off! The starter engaged and has been working fine for the last 5 days...

Eldo wrote:

OK, I admit that this doesn't really apply to this thread, but Aaron, I couldn't find a "just plain" Security System Problem thread with the Search function.........

ANYway, I just had something happen that I cannot find in the '98 FSM that I have in my computer (my car being a '97...)

In that GM SPO eManual, I have tracked down every thread and I can't find any example where the Security light stays on at ALL times - And by this I don't mean the usual "all" times, I mean Start, Run, Off, Open the damned doors and play with the keyfob kind of ON!!

While I actually got myself home, I can't find an electronic reason why I did. While I was trapped outside Safeway in the rain, the only thing that seemed possible to go after was the starter-relay, which is above the left footwell with the BCM & LCM, while the (solid-state) module is over the passenger side footwell...

I 'popped' the E-Brake once and literally pounded on the left-side trim piece with my foot,
and that stubborn Security lite went off! The starter engaged and has been working fine for the last 5 days...

this is going to happen on these cars increasingly...

you just had a "stuck" relay... What happens is over time the electrical contact material on the relay points "creeps" and forms a rough surface; the metal on one contact sinters onto the other... Eventually it gets rough enough for the contacts to stick closed sometimes. Fix is to replace relay, unless the relay is such you can disassemble it and replace/replate the contacts... I just replaced my brake and cruise control switches for the same reason, to get rid of an anomalous phantom turn signal blinking problem, they have relay-type contacts and after ~15 years (my 98-model car was built 11/97) they had crept. . The turn signal switch is worn for sure but not dead enough yet.

That was indeed my gut feeling Albert, the reason for my banging around the relay area. It was only afterward that I tried to find an explanation for the Security light staying lit - not to mention that a relay stuck closed ought to actually let the starter signal get thru...

Unless these schematics are wrong, the only thing I can see lighting the light is the PassKey module.

Eldo wrote:

That was indeed my gut feeling Albert, the reason for my banging around the relay area. It was only afterward that I tried to find an explanation for the Security light staying lit - not to mention that a relay stuck closed ought to actually let the starter signal get thru...

Unless these schematics are wrong, the only thing I can see lighting the light is the PassKey module.

It would not surprise me if the pass-key module was set up to clamp the security light on if something failed the start-up self-test - which if the relay was stuck should have been the case. Security system is **never** off (it's part of the famous parasitic load on these cars).

More directly, if you have an actual schmatic showing the internals of the circuitry in the passkey module then we could figure it out. If you have the FSM diagrams, the problem becomes that, assuming the schematics are right - we still don't have a circuit diagram for the pass-key module itself, so we can't really even guess well at the states and outputs.

I would pick a "maintenance" day in the future to replace the relay. I think it's called "anti theft relay" on rockauto.com - $11 to $24 bucks and a new one is yours...

Albertj

Enduring the 3 minute delay occasionally?
A key mod that may help:
If a cleaning doesn't do the trick, the problem may be aging/worn contacts on the resistor pellet. A friend of mine suggested an approach that runs contrary to key replacement, but works.
Rather than replacing the key, he trimmed some of the plastic on each side of the pellet, effectively raising the height of the contacts.
A free fix that works
In fact, replacement keys seem to have shorter (in length, not height) contacts than OEM keys and this may be problematic at times. Keeping the OEM key if possible might be wise.

Good idea! That would be something to try if the spare key is found to work. In my case, the spare key (like new condition) didn't make a difference, so I knew it was likely the module itself.

denim wrote:

Enduring the 3 minute delay occasionally?
A key mod that may help:
If a cleaning doesn't do the trick, the problem may be aging/worn contacts on the resistor pellet. A friend of mine suggested an approach that runs contrary to key replacement, but works.
Rather than replacing the key, he trimmed some of the plastic on each side of the pellet, effectively raising the height of the contacts.
A free fix that works
In fact, replacement keys seem to have shorter (in length, not height) contacts than OEM keys and this may be problematic at times. Keeping the OEM key if possible might be wise.

this works because if you look in the keyway the little paddle contacts get a groove worn into them.

denim wrote:

If a cleaning doesn't do the trick, the problem may be aging/worn contacts on the resistor pellet. A friend of mine suggested an approach that runs contrary to key replacement, but works.
Rather than replacing the key, he trimmed some of the plastic on each side of the pellet, effectively raising the height of the contacts.
A free fix that works

A brilliantly simple suggestion, Denim!

[+]